Shader Editor: graph multiple shader trees simultaneously
You can split your screen into as many Shader Editors as you want (which this post explains well) and pin a different node tree to each one.  You can also make parts of your textures reusable and instance them in other materials by making them a Node Group.  Then a change to the group will be reflected everywhere the group is used.
Say you have a part of a material you want to make reusable:

Select the nodes and press Ctrl + G to make a group.

The inputs and outputs will be made automatically depending on what was already in use.
You can copy and paste this Node Group to other materials, or pressing Shift + A and selecting Group you'll find it at the bottom of the menu.  My example has the default name NodeGroup.

You can see it is instanced because it will display the number of users.

You can also see that the Node Group can be used for different things in different materials.  You can group up as many nodes as you would like, indeed including BSDFs.
A change made inside the Node Group affects all of these objects.

This is where leaving one Shader Editor pinned inside the group may come in handy.  If you want a single user copy, you can make one by clicking on the button that displays the current number of users.